To forge one of this variety intended to have a separate crank-pin, only two components are necessary, one for the lever and the other for the axle proper. The forging of the axle-piece commences by either drawing down a piece whose sectional area is greater than that of the axle desired, or upsetting a smaller piece at that end which is to be welded to the lever, the object being to form a thick lump at the intended joint, to admit two or three welding heats.

The preparation of the shaft end for welding to the lever consists in either punching a hole into the upset part, or cutting a slit and forming a gap of the slit, for the purpose of fitting in the end of the lever. When a hole is punched, it is drifted with an oval or oblong drift, thus making the greatest width of the hole to be in line with the length of the shaft. The greatest width of the hole should be about 11/2 times the diameter of the shaft, and the shortest width about equal to the shaft's diameter.

The shaft end being thus prepared, the lever is selected or drawn down of a straight bar, until the sectional area and shape is that of the lever required. One end is next shaped to fit the hole or gap in the shaft; this shaping consists in drawing down and spreading out a stem at the lever end, the shape and dimensions of the stem being the same as those of the hole. At the junction of the stem with the thick part of the lever, a concave shoulder is formed, instead of a flat one. The hollow shoulder or bearing is made by driving in a fuller at each side of the stem; to do this conveniently, the thick end of the lever is put to the ground, and the fuller driven in at the two corners while the stem is upwards.

By thus hollowing the shoulder, it is made to partly resemble the circular form of the shaft; and when the two are welded together, a firm bearing and joint will be the result. When the lever and axle are fitted sufficiently near to each other for welding, the two components appear as in Fig. 181.

The method of welding consists in placing the two together in the furnace with the lever end upwards ; and when welding heat is obtained, the work is carefully swung out from the fire to the hammer, and, while still in the same relative position, the work is placed with the lower heated portion in an anvil-block having a half-round gap of suitable width. A few blows are then given to the upper end of the lever, which firmly weld the shoulder to the shaft. The work is next partly rotated by the rotator, and a few blows given to one side of the joint; after which it is partly rotated back again to present the opposite side of the joint to the hammer, and the welding is then continued. When thus partly united, another welding heat is given, and the joint finished by upsetting the shaft end with a pendulum-hammer, and with another upsetting of the lever and hammering of the joint sides, if necessary.

After the joint is made sufficiently solid and the boss part reduced to a suitable thickness and width, the superfluous metal is cut off, and the lever-boss is shaped with fullers and hammering to the desired form.